Disclosed is a new Transformerless Power Conversion System (TPCS) that allows a direct voltage step-up or step-down of DC or AC power without the use of magnetic core transformers. The operation is accomplished with solid state switching devices, capacitors, preferentially air core inductors and a switch control system.
The conversion and step-up from AC to DC and the inverse process can be implemented with high efficiency and without the generation of harmonics. The transformer elimination in conjunction with high inversion frequency operation results in a low weight system without transformer core losses and third harmonic generation. For high ratio DC to DC transformation the TPCS transports the input charge directly to the output without requiring an AC link. The three distinct operations of charging, transformation, and energy discharge are typically in sequential order and allows a complete isolation between the input and output power grids. The TPCS allows complete power flow control and with it allows an improvement of power grid stability. A number of integrated TPCS modules can be configured to perform in a single system as a voltage transformation stage, a power converter or inverter, an output regulator, an AC phase angle corrector as well as a fast power interruption device.
The architecture is specifically suited for high voltage DC power distribution systems with AC to DC conversion and step-up at the power station for HVDC transmission; DC to DC step down for DC distribution in place of AC; and final DC to polyphase AC power conversion near the bulk power consumers.